Alignment of transmitter clock signal and receiver clock signal may be accomplished by a receiver tracking phase of an incoming data signal. If the phase of the data signal is early with respect to the receiver clock signal, then the receiver may pump up an oscillator to increase the frequency or advance the phase of the receiver clock. Similarly, if a phase of the data signal is late with respect to the receiver clock signal, then the receiver may pump down an oscillator to decrease the frequency or retard the phase of the receiver clock. By pumping up or down the receiver clock, the receiver may maintain alignment between the receiver clock signal and the transmitter clock signal.